OC 40.4 - Effect of previous INR control on subsequent DOAC persistence and adherence, in patients switched from VKA to DOAC

Monday, June 26, 2023

15:30 – 15:45 ET

Room: 517

Session Available As: Live-Stream and On-Demand

Presenting Author(s)

Tessa Elling, MD

PhD student
Department of Hematology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
Groningen, Groningen, Netherlands

Co-Author(s)

EH

Eelko Hak

PhD, Professor of Clinical Pharmacoepidemiology
Groningen Research Institute of Pharmacy, Unit of Pharmacotherapy, -Epidemiology and Economy, University of Groningen, Groningen, the Netherlands.
Groningen, Groningen, Netherlands
JB

Jens Bos

BSc, Database manager
Groningen Research Institute of Pharmacy, Unit of Pharmacotherapy, -Epidemiology and Economy, University of Groningen, Groningen, the Netherlands.
Groningen, Groningen, Netherlands
VT

Vladimir Y. I. G. Tichelaar

MD PhD, Physician researcher
Department of Hematology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
Groningen, Groningen, Netherlands
NV

Nic Veeger

PhD, Clinical epidemiologist
Department of Epidemiology, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
Groningen, Groningen, Netherlands
Karina Meijer, MD, PhD (she/her/hers)

MD, PhD, Internist-haematologist, Professor
Department of Hematology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
Groningen, Groningen, Netherlands

Background: To optimize anticoagulation therapy, guidelines suggest a switch from vitamin K antagonist (VKA) to direct oral anticoagulant (DOAC) in patients with low time in therapeutic range (TTR < 70%). Such a low TTR could be caused by poor compliance. It is therefore possible that previous international normalized ratio (INR) control is associated with subsequent DOAC intake.

Aims: To evaluate the effect of previous INR control on DOAC non-adherence and non-persistence, in patients who switched from VKA to DOAC.

Methods: Patients who switched from VKA to DOAC between January 2012 and December 2019 were included using data from Certe Thrombosis Service, IADB pharmacy.nl community database University Groningen and Statistics Netherlands. DOAC prescriptions were used to determine non-persistence based on a 180-day prescription gap. DOAC non-adherence was calculated in persistent patients using the proportion of days covered (PDC), with a PDC < 90% defined as non-adherent. INR control (i.e. TTR, time under therapeutic range (TUR) and INR variability) was assessed over the 180 days before switch from VKA to DOAC. The association between INR control and DOAC non-persistence and non-adherence was evaluated by Cox regression models and logistic regression analyses respectively.

Results: 437 patients were included. Median TTR was 57.8% [IQR 41.1–73.7]. After 1 and 3 years of follow-up, DOAC non-persistence was 17.8% (95%CI 14.0-21.4) and 33.2% (95%CI 27.9-38.1) respectively. During the first 180 days after switch, 363 (89.5%) patients were adherent to DOAC. Low TTR was not associated with DOAC non-persistence (HR 1.07, 95%CI 0.74-1.54) nor with DOAC first 180-days non-adherence (OR 1.38, 95%CI 0.67-2.84). TUR and INR variability were also not associated with DOAC non-persistence nor non-adherence (table 1).

Conclusion(s): Previous INR control during VKA therapy is not associated with subsequent DOAC non-adherence and non-persistence. Therefore, INR control should not be used as a surrogate for predicting DOAC adherence or persistence.

Learning Objectives:

Upon completion, participants will be able to describe methods to evaluate INR control
Upon completion, participants will be able to describe adherence and persistence patterns on DOAC therapy in patients who switched from VKA to DOAC
Upon completion, participants will be able to describe the effect of previous INR control on DOAC adherence and persistence in patients who switched from VKA to DOAC